I was checking the wiki of oVirt yesterday when I saw something that I was not aware of : oVirt already support GlusterFS! Not everything is there and working 100% but it’s developing rapidly.
What amaze me is the fast evolution that free software enable. The first official release of oVirt is not 6 months old that I would not have enough space here to list all the new features that are being worked on. Go back 2 years in time when RHEV first came out : it was very promising but at the same time very far from the features set that VMware had. Look at RHEV/oVirt now and the fast pace of development since then.
If you want to try out oVirt and GlusterFS or see what it look like, someone posted a short tutorial on this at http://www.middleswarth.net/content/installing-ovirt-31-and-glusterfs-using-either-nfs-or-posix-native-file-system